|Title of Invention||
"DECONTAMINANT COMPOSITION FOR DECONTAMINATING A TOXIC AGENT AND PROCESS OF PREPARING THEREOF"
|Abstract||A chemical agent decontamination solution made up of about 3.5 to 6% of ammonium metavanadate, 20-35% tetrabutyl ammonium hydroxide and 0.5 to 6 % guar gum is provided. This solution is a non corrosive, nontoxic and nonflammable decontaminant.|
|Full Text||FIELD OF THE INVENTION
This invention relates generally to the field of compositions useful in decontamination of material, equipment and personnel exposed to toxic chemical agents.
BACKGROUND OF THE INVENTION
Methods for decontamination of chemical agents, which include a variety of organophosphorous and organosulphur compounds, are known in the art. However , these known methods use compositions which have certain undesirable properties, including corrosiveness, flammability and toxicity. For example, hypochlorite formulations are very corrosive and toxic. Additionally^nany decontaminants degrade upon exposure to water and carbon dioxide,requiring that these solutions be prepared and used the same day they are needed. Further, application of the hypochlorite decontaminant often requires substantial scrubbing for removal and destruction of the chemical agent, a procedure which limits its use.
One decontaminant, Decontamination solution (DS2), is useful against a variety of agents and contains 70% diethylenetriamine, 28% ethylene glycol monomethyl ether and 2% sodium hydroxide. However, DS2 will spontaneously ignite upon contact with hypochlorite and hypochlorite-based decontaminates. Further, DS2 may cause corrosion to aluminum., cadmium, tin, and zinc after prolonged contact, and softens and removes paint.
A need exists for a chemical agent decontamination solution which is noncorrosive, nontoxic, nonflammable and environmentally safe. Besides this decontaminant solution should also be cost effective therefore such reagents should be selected which have all the above stated properties and are also cheap to reduce the cost of the decontaminant solution.
Object of the Invention
An object of this invention is to develop a decontamination composition which effectively decontaminates chemical agents.
Another object of the invention is to develop a stable, non corrosive, non flammable and
effective decontaminant composition.
Yet another object of the invention is develop a cost effective decontaminant composition.
SUMMARY OF THE INVENTION
The invention provides a chemical agent decontamination composition comprising about 3.5 to 6%, by weight of ammonium metavanadate ,0.5-6% by weight of guar gum, 20-35% by weight of tetra butyl ammonium hydroxide and 65-70% by weight of water. Decontaminant of the invention may optionally contain buffers, catalysts and the Like. Advantageously,this composition is non toxic,noncorrosive and nonflammable. Other aspects and advantages of the present invention are described further in the following detailed description of the preferred embodiments thereof.
DETAILED DESCRIPTION OF THE INVENTION.
Decontamination of chemical compounds have focused primarily on chemical agents, particularly on nerve agents (such as G agents) and on the blistering agents ( such as mustard gas, or simply mustard).
Nerve agents are organbphosphorous compounds which disrupt the mechanism by which nerves transfers messages to the organs. These agents are fatal as poisoning by these agents leads to asphyxiation as control is lost over respiratory muscles. These agents are generally liquid at room temperature.
Oragnosulphur compounds like mustard gas are generally gases at room temperature and are termed as blistering agents or vesicants as these cause serious deep itching burning blisters on the skin when in contact with the human body. At very high concentrations, if inhaled, these cause bleeding and blistering within the respiratory system damaging the mucous membrane. Blister agent exposure over more than 50% body surface area is usually fatal.
As is already known in prior art ( U.S. Patent no.6566574 ) these agents can be detoxified by either substitution or hydrolysis. Hydrolysis of chemical toxic agents can be carried out with water, hydroxyl ions or other nucleophiles . The rate of hydrolysis of mustard and the nature of the products formed depends primarily on the solubility of the
agent in water and on the pH of the solution. In the detoxification of mustard, for example, the molecule first forms a cyclic sulfonium cation,which reacts with nucleophilic reagents(Yang, 1995). The dominant product is thiodiglycol but this product may react with sulfonium ions to give secondary intermediates.
The hydrolysis of Sarin (GB) occurs rapidly under alkaline conditions and gives the corresponding O-alkyl methylphosphonic acid. Catalytic species for acceleration of substitution reactions have been identified. One example is o-iodosobenzoate(IBA) which has been illustrated in an example by Moss & Zang(1993).The ISA compounds were also functionalized to introduce surface activiry(surfactant character) to active group(Moss et aL,1986) . Metal-ion amine complexes with surface active moiety were also developed and shown to exhibit catalytic effects in substitution reaction.
In the present disclosure a new species is disclosed which was identified to have catalytic effect on these reactions. Guar gum is a non-ionic polymer which has catalytic effect on hydrolysis of the above-stated toxants. Guar gum makes hydrogen bond with the target molecule and facilitate for hydrolysis.
Metal ions are added to guar gum to obtain a metal ion - guar gum complex which exhibits catalytic effect hi the hydrolysis reactions. To obtain these metal ion - guar gum complex an active ingredient is added to aqueous solution of guar gum. This active ingredient hi the present invention has been selected from a group of alkali vanadates , alkali molybdates and alkali azides. Non limiting examples of such compounds are ammonium molybdate, sodium molybdate, sodium azide and ammonium metavanadate.
The preferred active ingredient of the present invention is ammonium metavanadate. The active ingredient is in the range of 3.5 to 6 wt % of the total composition. The present invention provides a chemical agent decontamination formulation containing ammonium metavanadate of the invention which is non flammable and does not degrade significantly over time after exposure to atmospheric carbon dioxide and water.
The toxants to be neutralized by the present invention can be hi gaseous phase and can also be immmiscible hi water which is being used as the medium for decontamination. Hence a cationic hydrotrope (an ionic surfactant-like material with short hydrocarbon
chain) can be added,which increases the solubility of the toxant hi aqueous media, increases subsequent reaction rates between the reactive compound and the toxant, and significantly increases the physical stability and liquid-holding power and thus improves the overall effectiveness of neutralization of toxants by increasing the contact time of the decontamination solution with the toxant.
The cationic hydrotrope used in the present invention is quaternary ammonium salt with a short hydrocarbon chain. The quaternary ammonium salt is selected from the group consisting of tetrabutyl amino halides, tetrabutyl amino hydroxides, tetrapentyl ammo halides, tetrapentyl amino hydroxides, tetramethyl amino halides, tetramethyl ammo hydroxides, dimethyl benzyl amino hydroxides,trimethyl benzyl amino hydroxides and derivatives thereof.
The non limiting examples of cationic hydrotropes which can be utilized in the present invention are cetyltrimethyl ammonium hydroxide, benzalkonium hydroxide,tetrabutyl ammonium hydroxide and polymeric quaternary compounds .
In the present composition the said cationic hydrotrope preferably is tetrabutyl ammonium hydroxide and is in the range of 20% to 35% by weight of the total composition.
Thus the formulation of the present invention comprise a, a quaternary ammonium salt, an active ingredient as stated above and a catalytic species as stated above ; that when mixed with a carrier(such as water or seawater in a fluid phase) and exposed to a toxant, neutralizes the toxant.
The deconatminant of the invention may optionally contain preservatives, buffers, and reaction catalysts. Such components and the required amounts thereof, are well known and can be readily selected by one of skill in the art. See, e.g, Yang, et al., Chem. Rev.,92(8):1729(19192).
A water-based deconatminant of the invention appeared unchanged and is stable with respect to atmospheric exposure. Further , none of the components used in these compositions are listed as flammable or corrosive in the OSHRA Regulated Hazardous
Substances: Health,Toxicity,Economic and Technological Data, Occupational safety and Health administration of the U.S. Department of Labor, Noyes data Corporation(Park Ridge, N.J.,1990)
A preferred decontaminant composition of the present invention comprises '3.5% to 6% by weight active ingredient ,65% to 70% by weight of water, 20% to 35% by weight of a quaternary ammonium salt which is preferably tetrabutyl ammonium hydroxide and 0.5% to 6% of Guar gum powder.
To prepare the decontamination composition of the invention guar gum is dissolved in double distilled water the concentration of said aqueous solution of guar gum is in the range of 0.44 to 1,9%(w/v). To this solution active ingredient is added. The preferred active ingredient of the present invention is ammonium metavanadate ,which is added to this solution in the ratio of ammonium metavanadate to guar gum hi the range of 2.8:1 to 7.5:1. This forms a cross linked solution,which is dried at room temperature preferably in shadow. Dried cross linked solution is then crushed to form powder. This powder is then dissolved in a mixture of water and quaternary ammonium salt The quaternary ammonium salt used hi the present invention is tetrabutyl ammonium hydroxide and aqueous solution of tetrabutyl ammonium hydroxide as used above is 20 to 35% solution of tetrabutyl ammonium hydroxide hi water and 2.5 to 6.0 gm of powdered mixture as obtained above is added per 100 ml of this solution. Finally to obtain the final composition the pH of the solution is adjusted hi the range of 9 to 10. Generally 10% HC1 is used for adjusting the pH. 10% HCL was prepared by adding 53.5 ml 37.4% HCL to 146.5 ml distilled water.
The essential steps for the process comprise of
a) mixing active ingredient with aqueous guar gum solution followed by drying
and further crushing the dried mixture ;
b) mixing powdered mixture as obtained in step a with aqueous solution of
quaternary ammonium salt;
c) adding hydrochloric acid to the mixture of step b to adjust the pH of the
solution in the range of 9 to 10 to obtain the said composition.
In an exemplary embodiment of the process as described above 0.4 to 1.9 g of guar gum is dissolved in 90 to 100 ml of double distilled water. To this solution 3 to 5.5 g of oven dried ammonium metavanadate is added to obtain the cross linked solution containing the metal ion-guar gum complex.
This crosslinked solution is dried and crushed to a powder ,2.5 to 6.0 g of this powder is then added to 20 to 35% tetrabutyl ammonium hydroxide solution in water. The pH of the decanted solution was adjusted to about 9-10 to obtain the decontaminant composition of the present invention.
A particularly preferred deconatminant formulations of the invention is provided below. The approximate deconatminant fonnulations of the invention are provided below. The approximate weight percentages of the components of the formulations are provided hi columns A and B , respectively. Column 2 identifies the number of the component by reference to its accession number hi Chemical Abstracts Service.
In above table:
1. Deionized water as carrier
2. Tetrabutyl ammonium hydroxide as cationic hydrotrope and phase transfer
catalyst which enhance the miscibility of lipophilic CW agents in water.
3. Guar gum as the catalytic species for detoxifying the toxants.
4. Ammonium metavanadate as an active ingredient.
Thus, the decontaminant compositions of the invention are believed to be stable, nontoxic and useful in detoxifying/neutralizing a variety of chemical warfare agents, including organosulphur agents such as mustard gas (HD), and organosulphur agents such as the nerve agents termed sarin. Decontamination is effected by applying a decontaminant of the invention to the contaminated material, equipment, personnel or the like. Such application may be spraying,showering,washing or other suitable means.
The amount of decontaminant required under field conditions can be readily determined by one of skill in the art The decontaminant is typically used in a ratio approaching or exceeding 400:1 decontaminant : chemical agent. However, it has been tested under laboratory conditions at lower ratio of decontaminant to agent ( about 200:1).
These examples illustrate the preferred methods for preparing and applying the decontaminant of the invention. These examples are illustrative only and do not limit the scope of invention.
Water-Based Decontaminant Formulation: formulation of guar gum ammonium
metavanadate cross linked powder
Guar gum(0.8g) dissolved in 100 ml DD water, ammonium metavanadate(3.50 g) oven
dried added to guar gum solution. This form cross linked solution it is dried at room
temperature in shadow. Dried cross linked guar gum with ammonium metavanadate is
crushed to form powder. Cross linked powder (4.0 g) dissolved in 95 ml mixture of water
and tetrabutyl ammonium hydroxide in the ratio 3:1. Slowly the pH was adjusted to 9.5
by drop by drop adding 10% HCL solution . Stir for 1 hour .10% HCL:53.5 ml
HCL(37.4%) + 146.5 ml dH2O.
This formulation was used in the neutralization studies described below.
Neutralization of Chemical Warfare Agents
The following results illustrate the neutralization of mustard gas (HD) and one nerve agents using the above decontaminant formulation as described above and at a ratio of about 200:1 decontaminant: agent.
HD Neutralization Assay
The neutralization reactions were conducted under ambient conditions as follows 7 mg of HD (sulphur mustard,CAS Registry No.505-60-2) in a 13 X 100 mm culture tube was immediately Vortex mixed upon addition of 1.0 mL decontaminant. A 0.025 mL aliquot of the mixture was immediately withdrawn,and then added to and mixed with 1.0 mL n-butanol to quench the reaction. Serial dilutions, using n-butanol,were made to bring the concentration of the quenched reaction mixture into GC-FID 8610 gas chromatograph. The original mixture were withdrawn after specified time periods, and treated and analyzed in the manner just described. The method determined the amount of unneutralized HD; using the GC-FID result and the amount of HD originally present in the 0.025 mL aliquot, the percent neutralization was calculated.
The results are provided below.
NEUTRALIZATION OF GB
The neutralization reactions were conducted under ambient conditions. 1.0 mL of GB
(CAS Registry No 107-44-8) in a 13 X 100 mm culture tube was immediately Vortex
mixed upon addition of 1.0 mL decontaminant. A 0.025 mL aliquot of the mixture was
immediately withdrawn,and then added to and mixed with 4.97 mL 0.2M sodium
dihydrogen phosphate to quench the reaction.
The results are provided below:
The above results indicate that a water-based decontaminant of the invention will provide neutralization when used at a ratio typically found in field conditions, about 200:1 decontaminant agent
Numerous modifications and variations of the present invention are included in the above-identified specification and are expected to be obvious to one of skill in the art. Such modifications and alterations to the compositions and processes of the present invention are believed to be encompassed in the scope of the claims appended hereto.
1. A decontaminant composition for decontaminating a toxic agent, comprising
3.5% to 6% by weight of active ingredient selected from the group consisting of
alkali vanadates , alkali molybdates and alkali azides , 65% to 70% by weight of
water, 20% to 35% by weight of a quaternary ammonium salt and 0.5% to 6% by
weight Guar gum.
2. The decontaminant composition as claimed in claim 1, wherein the said
composition optionally comprises a buffer preservative.
3. The decontaminant composition as claimed in claim 1, wherein the said
quaternary ammonium salt is selected from the group consisting of tetrabutyl
amino halides ,tetrabutyl amino hydroxides, tetrapentyl amino halides
,tetrapentyl amino hydroxides, tetramethyl amino halides , tetramethyl amino
hydroxides ,dimethyl benzyl amino hydroxides,trimethyl benzyl amino
hydroxides and derivatives thereof.
4. The decontaminant composition as claimed in claim 1, wherein the said
quaternary ammonium salt is tetrabutyl ammonium hydroxide.
5. The decontaminant composition as claimed in claim 1, wherein the said active
ingredient is ammonium metavanadate.
6. The decontaminant composition as claimed in preceding claims, wherein the said
composition is prepared by the process comprising the following steps;
a) mixing active ingredient with aqueous guar gum solution followed by
drying and further crushing the dried mixture ;
b) mixing powdered mixture as obtained in step a with aqueous solution of a
quaternary ammonium salt;
c) adding hydrochloric acid to the mixture of step b to adjust the pH of the
solution in the range of 9 to 10 to obtain the said composition.
7. The process as claimed in claim 6 wherein, the concentration of said aqueous
solution of guar gum in step a is in the range of 0.44 to 1.9%(w/v).
8. The process as claimed in claim 6 wherein, in step a the said active ingredient is
ammonium metavanadate and the ratio of ammonium metavanadate to guar gum
is 2.8:1 to 7.5:1.
9. The process as claimed in claim 6 wherein, in step b the said quaternary
ammonium salt is tetrabutyl ammonium hydroxide and 2.5 to 6.0 gm of
powdered mixture as obtained in step a is added to 100 ml of 20 to 35% aqueous
solution of tetrabutyl ammonium hydroxide.
10. The decontaminant composition for decontaminating a toxic agent, substantially
as herein described with reference to foregoing examples.
|Indian Patent Application Number||682/DEL/2008|
|PG Journal Number||21/2013|
|Date of Filing||18-Mar-2008|
|Name of Patentee||DIRECTOR GENERAL, DEFENCE RESEARCH & DEVELOPMENT ORGANISATION|
|Applicant Address||DRDO BHAWAN, RAJAJI MARG, NEW DELHI-110 011, INDIA|
|PCT International Classification Number||C07D 405/00|
|PCT International Application Number||N/A|
|PCT International Filing date|